Circuit arrangement for delaying the charging of a capacitor

Claim 1

AUTOMATIC REGULATING ARRANGEMENT FOR DELAYING THE APPLICATION OF AN ABRUPT VOLTAGE CHANGE TO THE AUTOMATIC VOLUME CONTROL OF AN AMPLIFIER, PARTICULARLY OF AN AMPLIFIER EMPLOYED IN THE REGISTRATION OF SEISMIC IMPULSES, COMPRISING, IN COMBINATION, INPUT MEANS FOR INTRODUCING A DIRECT CURRENT INPUT VOLTAGE OF A PREDETERMINED NORMALLY CONSTANT AMPLITUDE BUT SUBJECT TO ABRUPT INCREASES OF SAID AMPLITUDE; VOLTAGE DIVIDER MEANS CONNECTED WITH SAID INPUT MEANS FOR DERIVING FROME SAID INPUT VOLTAGE A REFERENCE VOLTAGE AT ITS CENTER POINT, A MORE NEGATIVE VOLTAGE AT ONE END THEREOF AND A MORE POSITIVE VOLTAGE AT THE OTHER END THEREOF; A FIRST SERIES-COMBINATION OF ONE VARIABLE RESISTOR MEANS AND ONE CAPACITOR MEANS HAVING A VARIABLE CHARGING TIME CONSTANT AND BEING CONNECTED ACROSS THE ENDS OF SAID VOLTAGE DIVIDER MEANS; TRANSISTOR MEANS HAVING A BASE, AN EMITTER AND A COLLECTOR AND HAVING ITS COLLECTOR CONNECTED TO SAID ONE END OF SAID VOLTAGE DIVIDER MEANS AND ITS BASE CONNECTED TO A JUNCTION POINT BETWEEN SAID FIRST RESISTOR AND CAPACITOR MEANS; A SECOND SERIES-COMBINATION OF ANOTHER VARIABLE RESISTOR MEANS AND ANOTHER CAPACITOR MEANS HAVING ALSO A VARIABLE CHARGING TIME CONSTANT AND CONNECTED BETWEEN SAID EMITTER OF SAID TRANSISTOR MEANS AND SAID CENTER POINT OF SAID DIVIDER MEANS; AND OUTPUT MEANS CONNECTED WITH SAID CENTER POINT OF SAID DIVIDER MEANS AND WITH A JUNCTION POINT BETWEEN SAID SECOND RESISTOR AND CAPACITOR MEANS RESPECTIVELY, FOR DELIVERING A CONTROL SIGNAL CORRESPONDING TO THE CHARGE VOLTAGE OF SAID OTHER CAPACITOR MEANS, SO THAT SAID OTHER CAPACITOR MEANS IS NORMALLY CHARGED TO SAID INPUT VOLTAGE OF NORMALLY CONSTANT AMPLITUDE, BUT IS BEING CHARGED UP TO AN INCREASED VOLTAGE CORRESPONDING TO AN INCREASE OF SAID INPUT VOLTAGE AMPLITUDE DURING A TIME PERIOD DEPENDING UPON THE ADJUSTED TIME CONSTANT OF SAID SECOND SERIES-COMBINATION, SAID TIME PERIOD BEGINNING ONLY AFTER SAID ONE CAPACITOR MEANS HAS BEEN CHARGED UP TO SAID INCREASED VOLTAGE DURING A PERIOD OF TIME DEPENDING ON SAID ADJUSTED TIME CONSTANT OF SAID FIRST SERIES-COMBINATION.